If there's a pony level I swear to god I'll kill myself and take as many people I can with me

No idea why people still think it's a horse level. The models were jokingly named that to mess with dataminers / poke fun at their old 'logo' for Diablo3. The models the names were tied to were completely different.

Hopefully, though, the Cow level will be accessible unlimitedly once the conditions are met rather than locking itself if you knock-off the leader.